About 2,600 gallons of sludge was mistakenly pumped into Flat Creek in a wastewater spill Tuesday night, Gainesville Department of Water Resources officials estimated.

Horace Gee, Gainesville environmental services administrator, said the sludge dissipated with the streamflow and “sort of cleaned itself up pretty quickly.”

About 6:30 p.m. Tuesday, plant personnel at the Flat Creek Water Reclamation Facility on Old Flowery Branch Road were manually pumping sludge from the anaerobic digester into dewatering blend tanks to remove as much sludge as possible for scheduled maintenance, according to a city of Gainesville news release.

The workers turned on recycle clarifier pumps because of a high level of sludge in the clarifier, but they didn’t check the valve in the digester basement, which is normally directed to the dewatering blend tank. The valve was closed because of ongoing maintenance.

“As a result, the sludge that would have eventually drained to the stormwater pumping station entered Flat Creek,” the city of Gainesville said in the news release.

City officials said staff immediately turned off the pump once the wastewater spill was discovered.

Gee said an operator making routine rounds discovered the issue and the plant was back to running at normal operation within 30 minutes.

City staff walked the stream Wednesday morning from the Flat Creek plant to Lake Lanier to look for any potential water quality issues and found “no obvious signs on any detriment to the stream.”

“Everything’s back to normal,” Gee said.

Environmental compliance staff started required monitoring protocol Wednesday morning by posting signs where the sludge was pumped in and below the bridge, Gee said.

Hall County Environment Health, the U.S. Army Corps of Engineers and the Georgia Environmental Protection Division were notified of the spill.

While most people wouldn’t be in the water at this time of year anyway, Gee said the posted signs were important in the city doing its “due diligence” to keep citizens safe.